1. Field
Example embodiments of the present invention relate to a wafer structure and epitaxial growth method for growing the same, more particularly, to a GaN epitaxial growth method.
2. Description of the Related Art
A substrate on which an epitaxial layer is formed using an epitaxial growth method may be bent and many crystalline defects may arise in the epitaxial layer due to lattice mismatch and/or a difference in coefficients of thermal expansion between the substrate and the epitaxial layer.
Conventional art discloses a technique of using a porous buffer layer that absorbs internal stress. In this technique, the porous buffer layer is formed on a SiC substrate, and an epitaxial layer is formed on the porous buffet layer. Because the buffer layer is porous, it absorbs stress induced by lattice mismatch.
However, because the porous buffer layer may be formed using an anodization process, a conductive substrate should be employed, thus only limited kinds of materials may be used for the substrate. Also, the anodization method may be complicated and/or costly.